Aircraft employ a see and avoid function to mitigate the likelihood of mid-air collisions with other aircraft, referred to herein as an intruder aircraft, as required by Title14 Code of Federal Regulations (14 CFR) 91.111, 91.113, 1n3 91.181. When intruder aircraft approach the self aircraft, the crew may change their current flight path to a modified flight path so as to maintain a safe amount of separation between their aircraft and the intruder aircraft. The crew may effect a maneuver to maintain a safe separation distance from the intruder aircraft operating in the airspace. Although the “see and avoid” requirements stated in 14 CFR 91.111, 91.113, and 91.181 are described as right of way rules, the intent is to avoid collisions with other aircraft and to remain “well clear”. The function to avoid collisions shall be referenced Collision Avoidance. The function to remain “well clear” shall be referenced as Self Separation.
Guidelines for aircraft Self Separation may be used to pass well clear of the intruder aircraft in proximity to the self aircraft. Right-of-way rules as outlined in 14 CFR 91.113 may provide guidance to the crew of the self aircraft so that they determine an appropriate right turn or a left turn, referred to herein as lateral maneuvering.
On occasion, an intruder aircraft may come dangerously close to the self aircraft so as to present a possibility of a mid-air collision. Collision Avoidance rules define procedures for the crew to take to avoid mid-air collisions when their manned aircraft becomes too close to an intruder aircraft. Vertical maneuvering may be recommended by electronic-based collision avoidance systems to advise pilots to ascend or descend, referred to herein as a vertical maneuver, so that their manned aircraft will pass above or below the intruder aircraft so as to avoid a mid-air collision. Some collision avoidance systems may even automatically initiate a vertical flight maneuver.
In a manned aircraft situation, the crew of the manned aircraft realize, on occasion, that a modified flight path based on right-of-way rules may not be optimal. The crew of the manned aircraft have the choice to select an alternative modified flight path based upon the crew exercising good judgment in view of their known flight path and the flight paths of other intruder aircraft operating in their vicinity. Such good judgment is based on the experience and common sense of the crew. For example, rather than implementing a lateral maneuver by turning right in accordance with 14 CFR 91.113, the crew may implement an alternative lateral maneuver by turning left.
However, the absence of the crew in an unmanned aircraft system (UAS) [also known as unmanned aircraft vehicle (UAV)] complicates the process of maintaining safe separation between the UAS and other aircraft. Here, the operator of the UAS is remote from the UAS. Accordingly, the remote UAS operator must rely on various electronic-based systems, such as radar and/or imaging technologies, to be aware of other aircraft in the vicinity of the UAS.
Legacy flight control algorithms operating a traditional UAS are not able to exercise good judgment to arrive at a conclusion that a modified flight path may be preferred over a modified flight path that is based 14 CFR 91.113. Hopefully, the remote UAS operator's situational awareness will be sufficiently high so that the remote UAS operator will realize the potential danger of turning the UAS onto a less than optimal modified flight path, and alternatively, realize that a different modified flight path may be preferred. However, reliance on a remote UAS operator, who may even be operating multiple UASs, to exercise good judgment in all circumstances may not be acceptable, especially in regions of airspace with high levels of aircraft traffic. Accordingly, there is a need in the arts to automatically emulate right-of-way rules using electronic systems in a fashion that more closely emulates the good judgment that would be exhibited by a crew onboard a manned aircraft.